Choosing block with the right type of bearing can be just as important as choosing a block with the right working load. But it is not as complicated at it may seem. We walk you through the three most common alternatives: plain bearings, ball bearings and roller bearings.
A plain bearing block has a solid sheave that rotates around a central hub. This is the most common block typ used on a boat, and the best alternative for static high load applications. However, a high quality plain bearing block can be used with good performance in any position on a boat. It has very few moving parts, which results in a long lifespan, no maintenance and great value for the money.
This type of block has small spherical balls arranged around the center of the bearing. The balls have a very small contact surface, which results in extremely low friction in low loads. Hence, high quality ball bearing blocks can be an excellent choice for low load applications. However, due to the small contact surface, the ball bearings easily deform under heavier loads, eventually resulting in jamming of the block.
At this stage, Rutgerson does not produce any ball bearing blocks.
A roller bearing block has cylindrical rollers arranged around the center of the bearing. The friction on a roller bearing block is just as low as on a ball bearing block, but due to the larger area transferring the load it continues to roll with low friction also under high loads. This makes high quality roller bearing blocks the best performing alterative for dynamic high load applications.